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I went up to Palomar this past weekend, it was pretty warm (85F), on the way up that popular twisty section, saw my DAM dropped to 0.5xx and ruined the fun for me. After that, I tried to stay out of boost per the comments i read when DAM drops. but going up a steep hill, sometimes I had to/was in low boost. Engine seems normal.

AC was Off. had some FKL and FBK, lowest was -4.xx. Intake Temp Manifold was peaking at 160F. AFL looks fine. And this weekend even cruising i get DAM dropped to 0.75. Always been using Shell 91 V-power. My car is a 2017 with ~6.5k on it, all stock except for Cobb AP ots stage 1 map.

Is this normal? Now I really want to get EGR/TGV delete and tune.. with the hot summer coming. Is the WRX really that delicate stock when running crappy ACN gas?

I am running stage 2 Torqued Performance e-tune. Intake Manifold temperatures between 120F-150F cruising in 85-90F heat.Since the hotter weather, I am experiencing more knock, but no DAM drop. I am thinking it is time to upgrade my TMIC/Chargepipe and deleting the EGR along with a retune.

I am running stage 2 Torqued Performance e-tune. Intake Manifold temperatures between 120F-150F cruising in 85-90F heat.Since the hotter weather, I am experiencing more knock, but no DAM drop. I am thinking it is time to upgrade my TMIC/Chargepipe and deleting the EGR along with a retune.

Also, you should switch from TP to Phatbotti for your etunes. I recently did this and immediately saw great results. It's a little more expensive but worth it to never see knock.

So for my case, it's more of a tune issue then, i assume. Since Cobb doesn't have Stage 1 OTS map for ACN91, they only have for 91 Octane. The 91 Oct OTS map is pulling timing due to hot weather and crappy gas. Also maybe elevation change for my case.

I should get a tune. I'll wait a bit till i get the parts and then do it. If you see anything wrong with my logic, please let me know. Thanks for sharing your feedback with your setup/tunes.

I plan on doing dyno tune. But since it's more expensive, i will will wait till i can get all the parts i want, which will be EGR/TGV delete, ECBS, and intercooler/charge pipe. I already have some parts in, still waiting on more. Also researching between different TMICs.

Phatbotti is pretty popular and I'm not too far away. What about Metro Performance in Murietta/Temecula? (http://www.metroperformance.net/) They are a bit closer to me. I hear good things through word of mouth for them.

This is the exact topic I've been looking for! my 91 stage 1 tune for my 2016 WRX was at 1.000 from October through March. As soon as temperatures hit consistent 60s and 70s, my DAM has dropped significantly, and is currently at .562. my next step is to clean the MAF sensor, but the weather seems to be the only variable. Does reflashing the ECU back to stock, then back to the 91 tune make any different depending on the weather?? Not trying to hijack the thread, but this seems to tie into the OP question/issue.

This is the exact topic I've been looking for! my 91 stage 1 tune for my 2016 WRX was at 1.000 from October through March. As soon as temperatures hit consistent 60s and 70s, my DAM has dropped significantly, and is currently at .562. my next step is to clean the MAF sensor, but the weather seems to be the only variable. Does reflashing the ECU back to stock, then back to the 91 tune make any different depending on the weather?? Not trying to hijack the thread, but this seems to tie into the OP question/issue.

You're not hijacking at all man. I also want to know the reasoning behind DAM drop in your case. I wouldn't recommend re-flashing or resetting the ECU, let your ECU learn the conditions and bring DAM back to 1. As to why it dropped, i'm still not entirely sure. but having custom tune from reputable tuners seems to be the best in terms of reducing knock for tune specific to your car(mods), gas & ambient environment.

I plan on doing dyno tune. But since it's more expensive, i will will wait till i can get all the parts i want, which will be EGR/TGV delete, ECBS, and intercooler/charge pipe. I already have some parts in, still waiting on more. Also researching between different TMICs.

Phatbotti is pretty popular and I'm not too far away. What about Metro Performance in Murietta/Temecula? (http://www.metroperformance.net/) They are a bit closer to me. I hear good things through word of mouth for them.

Thanks for info

Ron is one of the best FA20 tuners PERIOD. I've heard good things about Metro but seems like they work on older years and EJ's more than anything. Ron is proven time and time again to be of the best, if not THE best.

Quick update. without opting for a tune yet due to cost, I've got my 91 tune still, but I put some octane boost in a full tank of 91 gas, and cleaned the MAF sensor. I was hoping the octane boost would help get some consistent zeros on knock, and ultimately help the DAM creep back up. after a 30 minute drive on the interstate, i went from .562 to .625, but it would not go any higher. I think I'm going drive easy for this tank of gas and see how the ECU learns over the course of the next week. fingers cross for some more improvement. After staying at 1.000 for all of winter, the sudden inconsistencies just don't make sense

P.S. I'm not in So Cal, so it was 20 degrees in the winter at a solid 1.000, now i'm getting these DAM problems at 70-80 degrees...if that matters.

Quick update. without opting for a tune yet due to cost, I've got my 91 tune still, but I put some octane boost in a full tank of 91 gas, and cleaned the MAF sensor. I was hoping the octane boost would help get some consistent zeros on knock, and ultimately help the DAM creep back up. after a 30 minute drive on the interstate, i went from .562 to .625, but it would not go any higher. I think I'm going drive easy for this tank of gas and see how the ECU learns over the course of the next week. fingers cross for some more improvement. After staying at 1.000 for all of winter, the sudden inconsistencies just don't make sense

P.S. I'm not in So Cal, so it was 20 degrees in the winter at a solid 1.000, now i'm getting these DAM problems at 70-80 degrees...if that matters.

vs6p5gg Would love to hear updates on your situation as well!

DAM always takes a while to come back on. When I was on the MAPerformance tune it dropped to .625 once and took over a week to come back up to 1.000. From what I've heard you need to drive consistently with low/no knock readings for it to come back up to normal.

DAM always takes a while to come back on. When I was on the MAPerformance tune it dropped to .625 once and took over a week to come back up to 1.000. From what I've heard you need to drive consistently with low/no knock readings for it to come back up to normal.

Good call. I went for another 30 min drive on the interstate with my octane boosted 91 gas and my DAM has increased from .625 to .938 (or something like that). I'm feeling much better about that.

I still think the ambient temps are the culprit for the sudden changes in DAM over the last month, but I'll stick with 93 gas with my 91 map from now on and hopefully can hold onto a .9 or above DAM for most of the summer.

Now I wish Cobb would come up with a good OTS map for TGV deletes. If a protune wasn't necessary, I think that would be the best bang for your buck!

I have a Bren Tuning protuned 17 Wrx (GS Catless J pipe, GS TMIC and Charge Pipe, GS EBCS, Cobb Big SF Intake, TGV delete and EGR unplugged. And yesterday the temp was in the 80s which I live in MA so we just came out of a cold winter and now I also had significant spike in knock and my DAM dropped and has not returned back to 1 yet. See the attached pic. Also im pretty sure I was over boosting, my target is 19ish and i hit as high as 22.4.What do you guys think?

umm, i thought if you get rid of EGR, it would help reducing knocks since the hot exhaust gas is not recirculated back. But your case still didn't help.

Maybe you can try logging "Intake Temp Manifold" instead of Oil temp? if you catch another DAM drop in hot weather, would like to know what kind of ITM numbers you're seeing.

Either that or you got a bad batch of gas, i assume.

So for my case, i haven't have anymore hot days lately, so i haven't seen any unsual big knocks or DAM drop. when it gets hot again I will pay attention if my DAM drops or have big knock. If i do have DAM drop again, I will also try mixing in 1 gallon of e85 to see if that helps any.

I've never seen 190 temps and I live in the AV and go to vegas every month for reserves drill. Last trip it was 110 and that loooooong climb out of baker had my boost at 2-3 psi the whole way up and dam dropped to .375~. not really any way out of it. Instead of blowing up these cars just retard timings preemptively sometimes.

I went up to Palomar this past weekend, it was pretty warm (85F), on the way up that popular twisty section, saw my DAM dropped to 0.5xx and ruined the fun for me. After that, I tried to stay out of boost per the comments i read when DAM drops. but going up a steep hill, sometimes I had to/was in low boost. Engine seems normal.

AC was Off. had some FKL and FBK, lowest was -4.xx. Intake Temp Manifold was peaking at 160F. AFL looks fine. And this weekend even cruising i get DAM dropped to 0.75. Always been using Shell 91 V-power. My car is a 2017 with ~6.5k on it, all stock except for Cobb AP ots stage 1 map.

Is this normal? Now I really want to get EGR/TGV delete and tune.. with the hot summer coming. Is the WRX really that delicate stock when running crappy ACN gas?

I went up to Palomar this past weekend, it was pretty warm (85F), on the way up that popular twisty section, saw my DAM dropped to 0.5xx and ruined the fun for me. After that, I tried to stay out of boost per the comments i read when DAM drops. but going up a steep hill, sometimes I had to/was in low boost. Engine seems normal.

AC was Off. had some FKL and FBK, lowest was -4.xx. Intake Temp Manifold was peaking at 160F. AFL looks fine. And this weekend even cruising i get DAM dropped to 0.75. Always been using Shell 91 V-power. My car is a 2017 with ~6.5k on it, all stock except for Cobb AP ots stage 1 map.

Is this normal? Now I really want to get EGR/TGV delete and tune.. with the hot summer coming. Is the WRX really that delicate stock when running crappy ACN gas?

My WRX had a few episodes of that. Car driving PERFECT, driving to Arizona and Vegas on a separate occasions and boom knock feedbacks and DAM drops. Any attempt to build boost would trigger FKL and FBK and lower DAM. After the long weekend I was almost home, about 1hr away, I was pretty home in my home area. The car started working fine again, I was able to do multiple pulls back to back with 0 issues. Took it to my tuner and he never spotted anything fishy.. The fact that it happened TWICE with the same symptoms worried. The engine is gone now, but it was a good half year since the last episode and I was pushing 70 more WHP before engine went out.

Actually, i just tried that this past two weeks, and so far no DAM drop or big knocks more than the -1.41 norm. and weather got up to high 80s in SD when i was cruising. My intake manifold temp actually got up to 160 deg F at one point!
I've mixed 1 gallon of e85 for a full tank of ACN91. So far so good, this might be my temporary remedy until i get the parts and tune.

Zcypot, holy crap, that's scary. best of luck to you if you got a new car/engine.

Great post. I have a 2015 wrx and live in socal as well and i can agree that with the warming weather, I too have a drop of DAM as well. I only noticed as I am planning on installing tgv deleted, deleting egr, add gs tmic and gs charge pipe and work with my current e-tuner Eric from TP.

I refueled on Friday (same place i always go) reached out to tuner for a new map that i can log the parts going in, and that's when i started using my AP again to make sure its updated , i have all thing things he wants me to log, and that's when i saw my guage say dam was like at .875 or something like that.

Figured I must have picked up bad gas, but then I came across this and I guess I am not the only one having this come up around this same time. So it's gotta be the weather. Anyway i hope with the new parts plus retune, that I should see things go back to normal and enjoy a nicer happier car.

Great post. I have a 2015 wrx and live in socal as well and i can agree that with the warming weather, I too have a drop of DAM as well. I only noticed as I am planning on installing tgv deleted, deleting egr, add gs tmic and gs charge pipe and work with my current e-tuner Eric from TP.

I refueled on Friday (same place i always go) reached out to tuner for a new map that i can log the parts going in, and that's when i started using my AP again to make sure its updated , i have all thing things he wants me to log, and that's when i saw my guage say dam was like at .875 or something like that.

Figured I must have picked up bad gas, but then I came across this and I guess I am not the only one having this come up around this same time. So it's gotta be the weather. Anyway i hope with the new parts plus retune, that I should see things go back to normal and enjoy a nicer happier car.

I have all these same mods with a protune from Bren Tuning and also had the same issues when warmer weather arrived.

The DIT WRX’s have really picky ecus. I have tuned many of them, and they are super knock sensitive. Gas quality has a huge impact on how well they run, especially when adding hard parts and tuning. The best way to test if the ignition timing is too aggressive is to fill up with a new tank of 93 octane and add a bottle of octane booster. If the DAM stays at 1.0 the entire tank of gas, it points towards the ignition timing being too aggressive.

So today I added a bottle of Octane Booster and to my surprise my knock is way less. The most I saw was a FBK of -1.41. However, this was only a 30 mile drive. I will do more testing later today when the higher temps arrive.